1. Field of the Invention
The invention relates to skip stitch sewing machines which include needle bar latching and releasing mechanisms.
2. Description of the Prior Art
Skip stitch mechanisms, such as shown for example, in U.S. Pat. No. 3,782,311 of Kenneth D. Adams and Salvatori A. D'Orio for "Simplified Basting Stitch Mechanism" issued Jan. 1, 1974, and in U.S. Pat. No. 4,312,284 of Kenneth D. Adams for "Needle Bar Deflecting Arrangement for a Skip Stitch Sewing Machine" issued Jan. 26, 1982, include a normally engaged needle bar latch which is opened whenever the needle bar is jogged by a gate to a predetermined maximum lateral position on one side of a central needle bar position. The needle bar is thereby disconnected from actuating mechanism for imparting endwise reciprocatory motion thereto and a skipped stitch results. When the latch is opened to disconnect the needle from the actuating mechanism, the needle bar is drawn upward by an elevating spring into a limited position from which the needle bar may subsequently be reconnected to the actuating mechanism. The limited position is defined by a cantilevered spring with an arm which is normally supported in a flexed condition on an adjustable bracket and which projects therefrom to engage needle bar affixed structure at an offcenter location relative to the needle bar axis when the unlatched needle bar is drawn upwardly by the elevating spring. The cantilevered spring brings the needle bar to an abrupt halt. The spring therefor does little to cushion movement of the needle bar into the limited upward position and an undesirable level of impact noise is experienced as a result. The unsymmertical loading of the needle bar by engagement of the spring arm with the needle bar affixed structure also results in the production of undesirable noise during operation of the skip stitch mechanism.
It is a prime object of the present invention to provide a coiled needle bar cushioning spring which mounts upon the movable gate of a skip stitch sewing machine in axial alignment with the needle bar axis, and which can be positionally adjusted as a unit to predetermine a limited upward position for the needle bar when unlatched from actuating mechanism.
It is another object of the invention to provide an adjustable cushioning spring arrangement as described which is effective in sewing machines to minimize noise due to the operation of skip stitch mechanism.
It is also an object of the invention to provide an adjustable cushioning spring arrangement which can be economically produced and easily assembled into a machine.
Other objects and advantages of the invention will become apparent during a reading of the specification taken in connection with the accompanying drawings.